The mechanism of reverse transcription of viral or natural mRNAs is being studied with emphasis to increase size, yield and representation of DNA products. The role of RNase H in the transcription process has not been investigated due to the lack of specific inhibitors who preferentially block this site without affecting the polymerase activity. Several 2', 3', cyclic nucleotides have been shown to exert such a specific inhibition. Therefore, the transcription process will be investigated in the presence of these cyclic nucleotides. In addition, we will be examining the possibility whether reverse transcriptase is phosphorylated in vivo and if this in turn regulates the transcription process. The effect of phosphorylated enzyme in vitro will also be investigated in an effort to see if such enzymatic modification affects transcription.